Atorvastatin efficiency after traumatic brain injury in rats

The protective effects of statins in traumatic brain injury

Traumatic brain injury (TBI), often referred to as the "silent epidemic", is the most common cause of mortality and morbidity worldwide among all trauma-related injuries. It is associated with considerable personal, medical, and economic consequences. Although remarkable advances in therapeutic approaches have been made, current treatments and clinical management for TBI recovery still remain to be improved. One of the factors that may contribute to this gap is that existing therapies target only a single event or pathology. However, brain injury after TBI involves various pathological mechanisms, including inflammation, oxidative stress, blood-brain barrier (BBB) disruption, ionic disturbance, excitotoxicity, mitochondrial dysfunction, neuronal necrosis, and apoptosis. Statins have several beneficial pleiotropic effects (anti-excitotoxicity, anti-inflammatory, anti-oxidant, anti-thrombotic, immunomodulatory activity, endothelial and vasoactive properties) in addition to promoting angiogenesis, neurogenesis, and synaptogenesis in TBI. Supposedly, using agents such as statins that target numerous and diverse pathological mechanisms, may be more effective than a single-target approach in TBI management. The current review was undertaken to investigate and summarize the protective mechanisms of statins against TBI. The limitations of conducted studies and directions for future research on this potential therapeutic application of statins are also discussed.

Neuro-Inflammation Modulation and Post-Traumatic Brain Injury Lesions: From Bench to Bed-Side

Head trauma is the most common cause of disability in young adults. Known as a silent epidemic, it can cause a mosaic of symptoms, whether neurological (sensory-motor deficits), psychiatric (depressive and anxiety symptoms), or somatic (vertigo, tinnitus, phosphenes). Furthermore, cranial trauma (CT) in children presents several particularities in terms of epidemiology, mechanism, and physiopathology-notably linked to the attack of an immature organ. As in adults, head trauma in children can have lifelong repercussions and can cause social and family isolation, difficulties at school, and, later, socio-professional adversity. Improving management of the pre-hospital and rehabilitation course of these patients reduces secondary morbidity and mortality, but often not without long-term disability. One hypothesized contributor to this process is chronic neuroinflammation, which could accompany primary lesions and facilitate their development into tertiary lesions. Neuroinflammation is a complex process involving different actors such as glial cells (astrocytes, microglia, oligodendrocytes), the permeability of the blood-brain barrier, excitotoxicity, production of oxygen derivatives, cytokine release, tissue damage, and neuronal death. Several studies have investigated the effect of various treatments on the neuroinflammatory response in traumatic brain injury in vitro and in animal and human models. The aim of this review is to examine the various anti-inflammatory therapies that have been implemented.

Antioxidant therapies in traumatic brain injury

Oxidative stress plays a crucial role in traumatic brain injury (TBI) pathogenesis. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) formed in excess after TBI synergistically contribute to secondary brain damage together with lipid peroxidation products (reactive aldehydes) and inflammatory mediators. Furthermore, oxidative stress, endoplasmic reticulum stress and inflammation potentiate each other. Following TBI, excessive oxidative stress overloads the endogenous cellular antioxidant system leading to cell death. To combat oxidative stress, several antioxidant therapies were tested in preclinical animal models of TBI. These include free radical scavengers, activators of antioxidant systems, Inhibitors of free radical generating enzymes and antioxidant enzymes. Many of these therapies showed promising outcomes including reduced edema, blood-brain barrier (BBB) protection, smaller contusion volume, and less inflammation. In addition, many antioxidant therapies also promoted better sensory, motor, and cognitive functional recovery after TBI. Overall, preventing oxidative stress is a viable therapeutic option to minimize the secondary damage and to improve the quality of life after TBI.

Evaluation of the Effect of Atorvastatin Administration on the Outcomes of Patients with Traumatic Brain Injury: A Double-blinded Randomized Clinical Trial

Background

Traumatic brain injury (TBI) is one of the common causes of long-term disabilities and mortality. This study aimed to evaluate the effect of atorvastatin administration on the Glasgow Coma Scale (GCS), Glasgow Outcome Scale (GOS), and Disability Rating Scale (DRS) in patients with TBI.

Methods

This double-blinded randomized clinical trial included 60 patients with TBI in Golestan Hospital of Ahvaz, Iran. After obtaining an informed consent from all patients, the patients were randomly assigned into two groups. For the intervention group, atorvastatin with a daily dose of 20 mg was used. The control group was administered the same amount of placebo for 10 days. Changes in the level of consciousness were measured using the GCS, and functional recovery rate in patients was measured by GOS and DRS in the third follow-up month.

Results

According to the obtained results, compared with the control group, the atorvastatin administration significantly increased the level of GCS and DRS within 2 - 3 months post-intervention and improved GOS since the tenth day after the study (P < 0.05).

Conclusions

The results revealed the positive effect of atorvastatin on the improvement of outcomes measurements such as GCS, DRS, and GOS in patients after moderate and severe TBI.

The Effect of Oral Simvastatin on the Clinical Outcome of Patients with Severe Traumatic Brain Injury: A Randomized Clinical Trial

Background

Despite recent promising pharmacological and technological advances in neurosurgical intensive care, the overall TBI-related mortality and morbidity remain high and still pose a major clinical problem. The aim of this study was to evaluate the effect of oral simvastatin on the clinical outcome of patients with severe TBI.

Methods

In a double-blind placebo-controlled randomized clinical trial a total of 98 patients with severe TBI in Imam Khomeini Hospital in Sari, Iran, were evaluated. Patients who meet the inclusion criteria were randomly allocated into two groups (n=49). In addition to supportive therapies, the intervention group received oral simvastatin (40 mg, daily) for 10 days, and the control group received the placebo (10 days). Patients' Glasgow coma scale (GCS) score, in hospital mortality, duration of mechanical ventilation and length of ICU and neurosurgery ward stay were evaluated during three-time intervals (T1: admission, T2: discharge and T3: one month after discharge).

Results

The percentage of conscious patients was 18.9% (7 cases) in the simvastatin group and 3.1% (1 case) in controls (P=0.06) at T2. One month after discharge (T3) the proportion of conscious patients significantly increased in the simvastatin group compared to control group (64.9 % versus 28.1 %; P=0.002). There was no significant difference for the mean of GCS score between the simvastatin group and control group at T1 (6.41 ± 1.30 versus 6.41 ± 1.28, respectively; P = 0.98). However, the mean score of GCS in patients who received simvastatin was significantly greater than controls at T2 and T3 (p<0.05). There was no significant differences between two group in-terms of length of mechanical ventilation, ICU and neurosurgery ward stay.

Conclusion

According to the results of this study it seems that using simvastatin may be an effective and promising therapeutic modality for improving GCS score during TBI recovery.

Inflammation in Traumatic Brain Injury

There is an increasing evidence that inflammation contributes to clinical and functional outcomes in traumatic brain injury (TBI). Many successful target-engaging, lesion-reducing, symptom-alleviating, and function-improving interventions in animal models of TBI have failed to show efficacy in clinical trials. Timing and immunological context are paramount for the direction, quality, and intensity of immune responses to TBI and the resulting neuroanatomical, clinical, and functional course. We present components of the immune system implicated in TBI, potential immune targets, and target-engaging interventions. The main objective of our article is to point toward modifiable molecular and cellular mechanisms that may modify the outcomes in TBI, and contribute to increasing the translational value of interventions that have been identified in animal models of TBI.

Influence of Organic Solvents on Secondary Brain Damage after Experimental Traumatic Brain Injury

Many compounds tested for a possible neuroprotective effect after traumatic brain injury (TBI) are not readily soluble and therefore organic solvents need to be used as a vehicle. It is, however, unclear whether these organic solvents have intrinsic pharmacological effects on secondary brain damage and may therefore interfere with experimental results. Thus, the aim of the current study was to evaluate the effect of four widely used organic solvents, dimethylsulfoxide (DMSO), Miglyol 812 (Miglyol^®), polyethyleneglycol 40 (PEG 40), and N-2-methyl-pyrrolidone (NMP) on outcome after TBI in mice. A total of 143 male C57Bl/6 mice were subjected to controlled cortical impact (CCI). Contusion volume, brain edema formation, and neurological function were assessed 24 h after TBI. Test substances or saline were injected intraperitoneally (i.p.) 10 min before CCI. DMSO, Miglyol, and PEG 40 had no effect on post-traumatic contusion volume after CCI; NMP, however, significantly reduced contusion volume and brain edema formation at different concentrations. The use of DMSO, Miglyol, and PEG 40 is unproblematic for studies investigating neuroprotective treatment strategies as they do not influence post-traumatic brain damage. NMP seems to have an intrinsic neuroprotective effect that should be considered when using this agent in pharmacological experiments; further, a putative therapeutic effect of NMP needs to be elucidated in future studies.

Mortality and Associated Morbidities Following Traumatic Brain Injury in Older Medicare Statin Users

OBJECTIVE

To assess the relationship between posttraumatic brain injury statin use and (1) mortality and (2) the incidence of associated morbidities, including stroke, depression, and Alzheimer's disease and related dementias following injury.

SETTING AND PARTICIPANTS

Nested cohort of all Medicare beneficiaries 65 years of age and older who survived a traumatic brain injury (TBI) hospitalization during 2006 through 2010. The final sample comprised 100 515 beneficiaries.

DESIGN

Retrospective cohort study of older Medicare beneficiaries. Relative risks (RR) and 95% confidence interval (CI) were obtained using discrete time analysis and generalized estimating equations.

MEASURES

The exposure of interest included monthly atorvastatin, fluvastatin, lovastatin, pravastatin, rosuvastatin, and simvastatin use. Outcomes of interest included mortality, stroke, depression, and Alzheimer's disease and related dementias.

RESULTS

Statin use of any kind was associated with decreased mortality following TBI hospitalization discharge. Any statin use was also associated with a decrease in any stroke (RR, 0.86; 95% confidence intervals (CI), 0.81-0.91), depression (RR, 0.85; 95% CI, 0.79-0.90), and Alzheimer's disease and related dementias (RR, 0.77; 95% CI, 0.73-0.81).

CONCLUSION

These findings provide valuable information for clinicians treating older adults with TBI as clinicians can consider, when appropriate, atorvastatin and simvastatin to older adults with TBI in order to decrease mortality and associated morbidities.

Potential immunotherapies for traumatic brain and spinal cord injury

Traumatic injury of the central nervous system (CNS) including brain and spinal cord remains a leading cause of morbidity and disability in the world. Delineating the mechanisms underlying the secondary and persistent injury versus the primary and transient injury has been drawing extensive attention for study during the past few decades. The sterile neuroinflammation during the secondary phase of injury has been frequently identified substrate underlying CNS injury, but as of now, no conclusive studies have determined whether this is a beneficial or detrimental role in the context of repair. Recent pioneering studies have demonstrated the key roles for the innate and adaptive immune responses in regulating sterile neuroinflammation and CNS repair. Some promising immunotherapeutic strategies have been recently developed for the treatment of CNS injury. This review updates the recent progress on elucidating the roles of the innate and adaptive immune responses in the context of CNS injury, the development and characterization of potential immunotherapeutics, as well as outstanding questions in this field.

Phase II Clinical Trial of Atorvastatin in Mild Traumatic Brain Injury

Statins constitute a class of medications commonly used in the treatment of elevated cholesterol. However, in experimental studies, statins also have other non-cholesterol-mediated mechanisms of action, which may have neuroprotective effects. The aim of this study was to determine whether administration of atorvastatin for 7 days post-injury would improve neurological recovery in patients with mild traumatic brain injury (mTBI). The hypothesis was that atorvastatin administration would reduce post-concussion symptoms and also that atorvastatin administration for 1 week post-injury would be safe. One hundred forty patients with mTBI were planned to be enrolled and randomly assigned to receive atorvastatin 1 mg/kg (up to 80 mg/kg) per day or placebo for 7 days starting within 24 h of injury. Assessments of post-concussion syndrome, post-traumatic stress and depressive symptoms, cognition, memory, verbal fluency, functional, and work status were performed at baseline, 1 week, and 1 and 3 months. The result on the Rivermead Post-Concussion Symptoms Questionnaire at 3 months was the primary outcome. Enrollment in the trial was stopped early because of difficulty in recruiting sufficient numbers of subjects. Fifty-two patients with mTBI were enrolled; 28 patients received atorvastatin and 24 received placebo. The median Rivermead score was 2 for the atorvastatin group, compared to 3.5 for the placebo group, at 3 months post-injury (χ2(1) = 0.0976; p = 0.7547). The change in the Rivermead score between baseline and 3 months was also analyzed. The median decrease in score was 4 for the atorvastatin group and 10.5 for the placebo group (χ2(1) = 0.8750; p = 0.3496). No serious adverse events occurred, and there was no significant difference in the incidence of adverse events in the two treatment groups. Atorvastatin administration for 7 days post-injury was safe, but there were no significant differences in neurological recovery post-mTBI with atorvastatin.

Impact of statins on cognitive deficits in adult male rodents after traumatic brain injury: a systematic review

The efficacy of statin treatment on cognitive decline is controversial, and the effect of statins on cognitive deficits in individuals with traumatic brain injury (TBI) has yet to be investigated. Therefore, we systematically reviewed the effect of statins on cognitive deficits in adult male rodents after TBI. After identifying eligible studies by searching four electronic databases on February 28, 2014, we assessed study quality, evaluated the efficacy of statin treatment, and performed stratified metaregression and metaregression to assess the influence of study design on statin efficacy. Eleven studies fulfilled our inclusion criteria from a total of 183 publications. The overall methodological quality of these studies was poor. Meta-analysis showed that statins exert statistically significant positive effects on cognitive performance after TBI. Stratified analysis showed that atorvastatin has the greatest effect on acquisition memory, simvastatin has the greatest effect on retention memory, and statin effects on acquisition memory are higher in closed head injury models. Metaregression analysis further showed that that animal species, study quality, and anesthetic agent impact statin effects on retention memory. We conclude that statins might reduce cognitive deficits after TBI. However, additional well-designed and well-reported animal studies are needed to inform further clinical study.

Rosuvastatin in experimental brain trauma: improved capillary patency but no effect on edema or cerebral blood flow

BACKGROUND

Microvascular dysfunction, characterized by edema formation secondary to increased blood-brain barrier (BBB) permeability and decreased blood flow, contributes to poor outcome following brain trauma. Recent studies have indicated that statins may counteract edema formation following brain trauma but little is known about other circulatory effects of statins in this setting. The objective of this study was to investigate whether statin treatment improves brain microcirculation early after traumatic brain injury, and whether microvascular effects are associated with altered production of nitric oxide and prostacyclin.

METHODS

After fluid percussion injury, rats were randomized to intravenous treatment with 20mg/kg of rosuvastatin or vehicle. Brain edema (wet/dry weight), BBB integrity ((51)Cr-EDTA blood to brain transfer), cerebral blood flow ((14)C-iodoantipyrine autoradiography), and number of perfused cortical capillaries (FITC-albumin fluorescence microscopy), were measured at 4 and 24h. NO and prostacyclin production was estimated from plasma concentration of the degradation products NO2- and NO3- (NOx) and 6-keto-PGF1-alpha, respectively. Sham injured animals were treated with vehicle and analyzed at 4h.

RESULTS

Trauma resulted in brain edema, BBB dysfunction, and reduced cortical blood flow, with no effect of statin treatment. Trauma also induced a reduction in the number of perfused capillaries, which was improved by statin treatment. Statin treatment led to increased NOx levels and reduced mean arterial blood pressure. 6-Keto-PGF1-alpha levels tended to increase after trauma, and were significantly reduced by rosuvastatin.

CONCLUSIONS

Rosuvastatin treatment may improve microcirculation after traumatic brain injury by preserved patency of cerebral capillaries. This effect is associated with increased NO and reduced prostacyclin production. No effect on brain edema or BBB integrity was found.

Effect of rosuvastatin on cytokines after traumatic head injury

Object

The favorable effect of statin treatment after traumatic brain injury (TBI) has been shown in animal studies and is probably true in humans as well. The objective of this study was to determine whether acute statin treatment following TBI could reduce inflammatory cytokines and improve functional outcomes in humans.

Methods

The authors performed a double-blind randomized clinical trial in patients with moderate to severe TBI. Exclusion criteria were as follows: prior severe disability; use of modifiers of statin metabolism; multisystem trauma; prior use of mannitol, barbiturates, corticosteroids, or calcium channel blockers; isolated brainstem lesions; allergy to statins; previous hepatopathy or myopathy; previous treatment at another clinic; and pregnancy. Patients were randomly selected to receive 20 mg of rosuvastatin or placebo for 10 days. The main goal was to determine the effect of rosuvastatin on plasma levels of tumor necrosis factor–α, interleukin (IL)–1β, IL-6, and IL-10 after 72 hours of TBI. Amnesia, disorientation, and disability were assessed 3 and 6 months after TBI.

Results

Thirty-six patients were analyzed according to intention-to-treat analysis; 19 patients received rosuvastatin and 17 received placebo. The best-fit mixed model showed a significant effect of rosuvastatin on the reduction of tumor necrosis factor–α levels (p = 0.004). Rosuvastatin treatment did not appear to affect the levels of IL-1β, IL-6, and IL-10. The treatment was associated with a reduction in disability scores (p = 0.03), indicating a favorable functional outcome. Life-threatening adverse effects were not observed.

Conclusions

The authors' data suggest that statins may induce an antiinflammatory effect and may promote recovery after TBI. The role of statins in TBI therapy should be confirmed in larger clinical trials. Clinical trial registration no.: NCT00990028.

Synergistic benefits of erythropoietin and simvastatin after traumatic brain injury

Simvastatin and recombinant human erythropoietin (rhEpo) are implicated as potential therapeutic candidates for traumatic brain injury (TBI). Prominent effects of simvastatin include its anti-inflammatory, neurotrophic and neuroregenerative actions studied in various models of neuronal injury. On the other hand, rhEpo has been shown to promote cell survival mechanisms by producing anti-apoptotic and cell proliferative actions. Beneficial effects of rhEpo and statin monotherapies have been well studied. However, there are no reports showing combined use of rhEpo and statins after TBI. This investigation examined if combined efficacy of cell proliferative ability of rhEpo along with the neuroregenerative ability of simvastatin will render maximum recovery in a controlled cortical impact (CCI) mouse model of TBI. Results showed that compared to baseline TBI, rhEpo was more effective than simvastatin in promoting cell proliferation while simvastatin was more effective than rhEpo in restoring axonal damage following TBI. Combined treatment with simvastatin and rhEpo maximally restored axonal integrity while simultaneously inducing greater proliferation of newly formed cells resulting in better functional recovery after TBI than either alone. This is the first study showing the efficacy of erythropoietin-simvastatin combinational therapeutic approach in achieving greater structural and cognitive recovery after TBI.

Cholesterol in Alzheimer's disease and other amyloidogenic disorders

The complex association of cholesterol metabolism and Alzheimer's disease is presented in depth, including the possible benefits to be gained from cholesterol-lowering statin therapy. Then follows a survey of the role of neuronal membrane cholesterol in Abeta pore formation and Abeta fibrillogenesis, together with the link with membrane raft domains and gangliosides. The contribution of structural studies to Abeta fibrillogenesis, using TEM and AFM, is given some emphasis. The role of apolipoprotein E and its isoforms, in particular ApoE4, in cholesterol and Abeta binding is presented, in relation to genetic risk factors for Alzheimer's disease. Increasing evidence suggests that cholesterol oxidation products are of importance in generation of Alzheimer's disease, possibly induced by Abeta-produced hydrogen peroxide. The body of evidence for a link between cholesterol in atherosclerosis and Alzheimer's disease is increasing, along with an associated inflammatory response. The possible role of cholesterol in tau fibrillization, tauopathies and in some other non-Abeta amyloidogenic disorders is surveyed.

Statins in traumatic brain injury

Traumatic brain injury (TBI) is a common cause of long-term neurological morbidity, with devastating personal and societal consequences. At present, no pharmacological intervention clearly improves outcomes, and therefore a compelling unmet clinical need remains. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or "statins," offer a potential novel therapeutic strategy for TBI. Statins are well tolerated, easy to administer, and have a long clinical track record in critically ill patients. Their side effects are well defined and easily monitored. Preclinical studies have shown significant benefit of statins in models of TBI and related disease processes, including cerebral ischemia, intracerebral hemorrhage, and subarachnoid hemorrhage. In fact, multiple mechanisms have been defined by which statins may exert benefit after acute brain injury. Statins are currently positioned to be translated into clinical trials in acute brain injury and have the potential to improve outcomes after TBI.